Self-holding resonant reed relay



June 23. 1964 l. M. sLATER ETAL 3,138,745

SELF`-HOLDING RESONANT REED RELAY Filed May 27, 1960 United States Patent O 3,138,745 SELF-HOLDING RESONANT REED RELAY Ira M. Slater, Clarence Huetten, and .lames J. Kaufmann, Indianapolis, Ind., assignors to P. R. Mallory & Co. Inc., Indianapolis, Ind., acorporation of Delaware Filed May 27, 1960, Ser. No. 32,368 8 Claims. (Cl. 317-147) The present invention relates to remote control systems utilizing relays and has particular pertinency to resonant reed relays, the reeds Iof which have frequency discriminating characteristics operative to close the contacts of the relay as long as the resonant reed frequency is applied thereto.

A resonant reed relay may be used for obtaining remote control for responsive devices, such as television receivers, actuating devices for personal paging systems, and alert systems. Resonant reed relays utilize the mechanical resonance of the reeds. This is ideal in that the reeds have a Q higher than that of electrical systems and are usually less expensive.

At the present time, such resonant reed relays as are available are used to operate general purpose relays which in turn operate the desired controls. However, in these relays, the actuated relay reeds continue to vibrate and cause the contacts to dwell a low percentage of each cycle in a manner such that voltages are built up in a tank capacitor connected across the coils of a general purpose relay. In suoh a system there must be a relay and a tank capacitor for each reed.

The present invention describes a self holding resonant reed relay. This relay handles the controlled loads directly and does not use the general purpose relays or their tank capacitors. Only one tank capacitor, in contradistinction thereto, is used across the coil of the self holding relay. This relay then accomplishes its remote control function in a much simpler manner since it accomplishes in one unit all the functions of the extra relays with their individual tank capacitors. Thus a considerable cost savings if afforded since four or more reeds are usually required for controlling devices such as a television receiver.

It is therefore a prime object of the present invention to provide an electromagnetic holding arrangement in a remote control device to hold the resonant reed contacts therein permanently closed as long as a discriminating resonant signal frequency is applied to said reeds.

Another object of the present invention is to provide in a remote control system resonant reed relays which do not require auxiliary relays or individual tank capacitors for the reeds to effectuate the desired contro-l of associated equipment.

Another object of the present invention is to provide a simple, economical and efficient self holding resonant reed relay for use in remote control systems.

Other objects of the invention will be apparent from the following description and accompanying drawings taken in connection with the appended claims.

The invention comprises the features of construction, combination of elements, arrangement of parts, and methods of manufacture and operation referred to above or which will be brought out and exemplified in the disclosure herein set forth, including the illustrations in the drawings.

In the drawings:

FIG. 1 is a profile View of the self holding resonant reed relay of the present invention as illustrating an ernbodiment thereof.

FIG. 2 is a top view of the self holding resonant reed relay of the present invention; FIG. 3 is an end view of the invention as taken along line 3 3 of FIG. 2; and FIG. 4 is an electrical circuit detailing the mode of operation of the self holding resonant reed invention.

3,138,745 Patented June 23, 1964 ICC Generally speaking, Ithe resonant reeds of ythe relay are constructed to have a resonance characteristic whereby they are tuned to resonate at four individual non-harmonic frequencies. For purposes of illustration such frequencies may be 90, 130, 170 and 2l() cycles per second. A receiver accepts the modulated signal and causes pulses of the specified frequency to appear across the relay coil. When the signal is applied, a tank capacitor causes the coil to have a D.C. bias with an A.C. ripple. The specific reed which is tuned to this A.C. ripple frequency then builds up very rapidly in amplitude, pulls away from its permanent magnet holder and is attracted to and held by the relay coil until the power is released on the coil. The reed closes its particular set of contacts as it approaches the coil. A circuit function is then accomplished. The permanent magnet immediately snaps the reed Iback to the od position when power is removed from the coil upon stoppage of the input signal. Thus the relay is self holding while the resonant frequency is applied and is inthe open condition and held there by the permanent magnet arms when there is no input.

The features of the self holding resonant reed relay can also be directed to a structure whereby an input signal of a determined frequency may be fed to multiple windings of an electromagnet with one winding connecting the input modulated frequency and another connected to a rectified voltage derived from said signal; the combined inputs creating a total inductance able to attract one of the reeds discriminatingly. The inductance due to the direct current signal alone would be incapable of attracting the reed to close electrical contacts associated therewith. This result is afforded in the present embodiment since the relay uses a direct current with a high ripple content at the desired resonant frequency and includes means for sustaining the magnetism in the magnetic circuit during the actuated time interval.

In FIGURES 1-3 of the drawings, there is shown the self holding resonant reed relay 9. It comprises a supporting mounting structure 10 upon which is placed a coil 11 having A.C. input terminals 12, 13. The coil surrounds an armature 14, and/or a pole piece 15. At the opposing end of `the mounting structure, a stack mounting 17 is connected which includes a plurality of fixed contact arms 18 having contacts 20 placed at the free ends 21v thereof. Individual terminals 22 are connected to the fixed ends of thecontact arms 18. Above the contact arms 18, individual reed arms 23, each tuned to a desired frequency, are placed. These individual reeds are fixed in the stack by hinge portions 70 and extend horizontallyrfrom the stack to have their free ends 25 overlie the pole piece of the coil of the relay 9. At the stack end lof the relay a permanent magnet 30 is placed above the fixed end of the reeds. At the top of the permanent magnet a plurality of sinuated steel arms 31 bear down against reed stiffeners connected to each of the tuned reeds. These reed stiffeners carry the mating contacts 33 to the fixed contacts 20 of the relay. The strength of the permanent magnet is such that in the unoperated condition, a magnetic force is applied so as to keep the contacts open until sufiicient forces are obtained due to the reeds vibrating in resonance, to separate them from the permanent magnet arms 31. Metal piece 35 is attached which will attract the resonant portions 71 toward the coil pole piece 15 upon a proper signal being applied to the relay coil 11.

In the operation of the relay when a signal is applied, a tank capacitor 40 placed across the relay coil, causes the coil to have a D.C. bias voltage with an A.C. ripple. This is so because when the signal is applied, a half wave series` connected rectifier 41 acts to allow a charging current to build up in the capacitor which will also allow a reverse discharge through the coil to be maintained when the signal is removed. When a signal is applied, the added rectifier voltage will be sufficient to pull the tuned reed away from the control of the permanent magnet and to close the circuit contacts. In actual practice, the motion of the reed is such that it appears to close the circuit instantly. Other reeds are not affected until each of their resonant frequencies is applied in turn to the coil. Each reed may be held in turn until all circuits .are closed provided the power is not removed from the coil while in the hold condition.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

What is claimed is:

1. A self holding resonant reed relay comprising a frame, an electromagnet including a coil having input leads for accepting a modulated input signal, a pole-piece for said electromagnet, said electromagnet mounted at one end of said frame, a multiplicity of tuned reeds, each reed being resonant at an individually determined frequency, said reeds fixed at the frame end opposite said electromagnet and having the free ends thereof extended to a point above said electromagnet, contacts placed on said reeds, fixed contact means connected to said frame, said contact means adapted to mate with said reed contacts, permanent magnet means attracting said reeds away from said fixed contacts to maintain the reed contacts and fixed contacts separated, means connected to said coil for exerting a residual bias therein, means adapted to feed pulsating direct current to said coil on the receipt of a modulated input signal thereby, said residual bias and said latter current being sufiicient to induce a magnetic force in the electromagnet to attract a reed resonant at said incoming signal frequency to said pole-piece and toy overcome the holding force of said permanent magnet on said reed, thereby allowing the reed contacts and the fixed contacts to meet to close a connected electric circuit.

2. A self holding resonant reed relay comprising a frame, an electromagnet including a coil having input leads for accepting a modulated input signal, a pole-piece for said electromagnet, said electromagnet mounted at one end of said frame, a multiplicity of tuned reeds, each reed being resonant at an individually determined frequency, said reeds fixed in a stack at a frame end opposite said electromagnet and having the free ends thereof extended horizontally to a point above said electromagnet, contacts placed on said reeds, fixed contact holding means connected to said stack in said frame, said contact holding means adapted to mate with said reed contacts, permanent magnet means attracting said reeds away from said fixed contacts to maintain the contacts normally open, means connected to said coil for creating a residual bias therein, means adapted to convert said modulated input signal into a pulsating direct current input to said coil, said residual bias and said latter current being sufficient to induce a magnetic force in the electromagnet to attract a reed resonant at said incoming signal frequency to said pole-piece and to overcome the holding force of said permanent magnet on said reed, thereby allowing the reed contacts and the fixed contacts to meet to close a connected electric circuit.

3. A self holding resonant reed relay comprising a frame, an electromagnet including a coil having input leads for accepting a modulated input signal, a polepiece for said electromagnet, said electromagnet mounted at one end of said frame, a multiplicity of tuned reeds, each reed being resonant at an individually determined frequency, said reeds fixed in a stack at a frame end opposite said electromagnet and having the free ends thereof extended horizontally to a point above said electromagnet, contacts placed on said reeds, fixed contact holding means connected to said stack in said frame, said contact holding means placed beneath said reeds and adapted to mate with said reed contacts, permanent magnet means attracting said reeds away from said fixed contacts to maintain the contacts normally open, bias means connected to said coil for creating a residual bias therein, means adapted to convert said modulated input signal into a pulsating direct current input to said coil, said residual bias and said latter pulsating current being sufficient to induce a magnetic force in the electromagnet to attract a reed resonant at said incoming signal frequency to said pole-piece and to overcome the holding force of said permanent magnet on said reed, thereby allowing the reed contacts and the fixed contacts to meet to close a connected electric circuit while said modulated input signal is present at said coil.

4. A self holding resonant reed relay comprising a frame, an electromagnet including a coil having input leads for accepting a modulated input signal, a pole-piece for said electromagnet, said electromagnet mounted at one end of said frame, a multiplicity of tuned reeds, each reed being respectively resonant at an individually determined frequency, said reeds fixed in a stack at a frame end opposite said electromagnet and having the free ends thereof extended horizontally to a point above said electromagnet, contacts placed on said reeds, fixed contact holding means placed adjacent said reeds and parallel thereto connected to said stack in said frame, said contact holding means placed beneath said reeds and adapted to mate with said reed contacts, permanent magnet means including sinuated metal arms attracting said reeds away from said fixed contacts to maintain the contacts normally open, bias means connected to said coil for creating a residual bias therein, means adapted to convert said modulated input signal into a pulsating direct current input to said coil, said residual bias and said latter current being sufficient to induce a magnetic force in the electromagnet to attract a reed resonant at said incoming signal frequency to said pole-piece and to overcome the holding force of said permanent magnet on said reed thereby allowing the reed contacts and the fixed contacts to meet to close a connected electric circuit while said modulated input signal is present at said coil.

5. A self holding resonant reed relay comprising a frame, an electromagnet including a coil having input leads for accepting a modulated input signal, a pole-piece for said electromagnet, said electromagnet mounted at one end of said frame, a multiplicity of tuned reeds, each reed being resonant at an individually determined frequency, said reeds fixed in a stack at a frame end opposite said electromagnet and having the free ends thereof extended horizontally to a point above said electromagnet, contacts placed on said reeds, fixed contact holding means placed adjacent said reeds and parallel thereto connected to said stack in said frame, said contact holding means placed beneath said reeds and adapted to mate with said reed contacts, permanent magnet means including sinuated metal arms placed above said reeds attracting said reeds away from said fixed contacts to maintain the contacts normaly open, bias means connected to said coil for creating a residual bias therein, means adapted to convert said modulated input signal into a pulsating direct current input to said coil, said residual bias and said latter current being sufficient to induce a magnetic force in the electromagnet to attract a reed resonant at said incoming signal frequency to said pole-piece and to overcome the holding force of said permanent magnet on said reed thereby allowing the reed contacts and the fixed contacts to meet to close a connected electric circuit while said modulated input signal is present at said coil.

6. A self holding resonant reed relay comprising a frame, an electro-magnet including a coil having input leads for accepting a modulated input signal, said coil surrounding a pole-piece, said electromagnet mounted at one end of said frame, a multiplicity of tuned reeds responsive only to determined frequencies fixedly mounted to said frame at an end opposite said coil, said reeds having free ends extending horizontally to points adjacent said pole of said electromagnet, metal pieces individually connected to said free ends of said reeds, a permanent magnet placed above said reeds at said xedly mounted end, contacts on said reeds, a plurality of contacts arms carrying contacts situated below said reeds contacts and spaced therefrom, said permanent magnet having joined thereto a multiplicity of metal arms extending horizontally therefrom above said reeds, said arms normally creating a magnetic force sufiicient to attract said reed contacts to hold the same away from said fixed contacts, a half-Wave rectifier placed in series with the input to said coil, a capacitor placed in parallel to said input between said rectifier and said coil, the free ends of said reeds being attracted to said pole-piece and held thereagainst when the proper modulated input signal is received by said coil, said residual bias in said coil and said rectifier modulated signal in said coil inducing a magnetic force sufficient to attract said free reed ends to said pole-piece and hold the same thereagainst for the time said signal persists, said contacts on said reeds thereby mating with said contacts on said fixed arms to close electrical circuits during such time.

7. A self holding resonant reed relay comprising a frame, an electromagnet including a coil having input leads for accepting a modulated input signal, said coil surrounding a pole-piece, said electromagnet mounted at one end of said frame, a multiplicity of tuned reeds responsive only to determined non-harmonic frequencies mounted to a stack in said frame at an end opposite said coil, said reeds having free ends extending horizontally above said pole of said electromagnet, metal pieces individually connected to said free ends of said reeds, a permanent magnet placed in said stack, contacts on said reeds, a plurality of contact arms carrying contacts situated below said reeds contacts and spaced therefrom, said permanent magnet having joined thereto a multiplicity of metal arms extending horizontally therefrom above said reeds, said arms normally exerting a magnetic force sufficient to attract said reed contacts to hold the same away from said fixed contacts, a rectifier placed in series with the input to said coil, a capacitor placed in parallel to said input between said rectifier and said coil, the free ends of said reeds being attracted to said pole-piece and held thereagainst when a properly modulated input signal is received by coil, a residual bias established in said coil thereby, and a rectified modulated signal in said coil inducing a magnetic force sufficient to attract a free reed end tuned to said signal to said pole-piece and hold the same thereagainst for the time said signal persists, said contacts on said reeds thereby mating with said contacts on said xed arms to close electrical circuits during such time.

8. A self holding resonant reed relay comprising a frame, an electromagnet including a coil having input leads for accepting la modulated input signal, said coil surrounding a pole-piece, said electromagnet mounted at one' end of said frame, a multiplicity of tuned reeds responsive only to determined frequencies fixedly mounted to said frame at an end opposite said coil, said reeds having free ends extending horizontally to points adjacent said pole of said electromagnet, metal pieces individually connected to said free ends of said reeds, a permanent magnet placed above said reeds at said fixedly mounted end, contacts on said reeds, a plurality of contact arms carrying contacts situated below said reed contacts and spaced therefrom, said permanent magnet having joined thereto a multiplicity of metal arms extending horizontally therefrom above said reeds, said arms normally exerting a magnetic force suiiicient to attract said reeds to hold the same away from said fixed contacts, a half-wave rectifier placed in series With the input to said coil, a capacitor placed in parallel to said input between said rectifier and said coil, the free ends of said reeds being attracted to said polepiece and held thereagainst when a properly modulated input signal is received by said coil, said capacitor establishing ya charge sufficient to residually bias said coil, said residual bias in said coil added to said rectifier modulated signal in said coil inducing a magnetic force sufficient to attract a free reed end having a similar frequency to said pole-piece and hold the same thereagainst for the time said signal persists, said contacts on said reeds thereby mating with said contacts on said xed arms to close electrical circuits during such time.

References Cited in the file of this patent UNITED STATES PATENTS 1,933,680 Ohl Nov. 7, 1933 2,105,134 Wintsch Jan. 11, 1938 2,368,953 Walsh Feb. 6, 1945 2,447,191 Lingel Aug. 17, 1948 2,513,360 Rahmel July 4, 1950 2,694,119 Armitage Nov. 9, 1954 3,001,048 Rhodes Sept. 19, 1961 

5. A SELF HOLDING RESONANT REED RELAY COMPRISING A FRAME, AN ELECTROMAGNET INCLUDING A COIL HAVING INPUT LEADS FOR ACCEPTING A MODULATED INPUT SIGNAL, A POLE-PIECE FOR SAID ELECTROMAGNET, SAID ELECTROMAGNET MOUNTED AT ONE END OF SAID FRAME, A MULTIPLICITY OF TUNED REEDS, EACH REED BEING RESONANT AT AN INDIVIDUALLY DETERMINED FREQUENCY, SAID REEDS FIXED IN A STACK AT A FRAME END OPPOSITE SAID ELECTROMAGNET AND HAVING THE FREE ENDS THEREOF EXTENDED HORIZONTALLY TO A POINT ABOVE SAID ELECTROMAGNET, CONTACTS PLACED ON SAID REEDS, FIXED CONTACT HOLDING MEANS PLACED ADJACENT SAID REEDS AND PARALLEL THERETO CONNECTED TO SAID STACK IN SAID FRAME, SAID CONTACT HOLDING MEANS PLACED BENEATH SAID REEDS AND ADAPTED TO MATE WITH SAID REED CONTACTS, PERMANENT MAGNET MEANS INCLUDING SINUATED METAL ARMS PLACED ABOVE SAID REEDS ATTRACTING SAID REEDS AWAY FROM SAID FIXED CONTACTS TO MAINTAIN THE CONTACTS NORMALY OPEN, BIAS MEANS CONNECTED TO SAID COIL FOR CREATING A RESIDUAL BIAS THEREIN, MEANS ADAPTED TO CONVERT SAID MODULATED INPUT SIGNAL INTO A PULSATING DIRECT CURRENT INPUT TO SAID COIL, SAID RESIDUAL BIAS AND SAID LATTER CURRENT BEING SUFFICIENT TO INDUCE A MAGNETIC FORCE IN THE ELECTROMAGNET TO ATTRACT A REED RESONANT AT SAID INCOMING SIGNAL FREQUENCY TO SAID POLE-PIECE AND TO OVERCOME THE HOLDING FORCE OF SAID PERMANENT MAGNET ON SAID REED THEREBY ALLOWING THE REED CONTACTS AND THE FIXED CONTACTS TO MEET TO CLOSE A CONNECTED ELECTRIC CIRCUIT WHILE SAID MODULATED INPUT SIGNAL IS PRESENT AT SAID COIL. 